Heat usually comes from a bad connection. In addition to checking the fuse contacts, also check the wire connections to the fuse holder. You may have to remove the panel.

Perhaps someone here can tell what current the motor normally draws (mine's not working). You can measure it at the fuse contacts and save having to go into the heater. Its also possible that something else on the same fuse is drawing to much current.

Are you using the glass type fuses?